Chapter 1 - Equations and Inequalities - 1.8 Absolute Value Equations and Inequalities - 1.8 Exercises - Page 168: 64

$\{-\frac{2}{3} \}$

Step 1. As an absolute value returns a positive number or zero, the only case for the inequality to be true is that $|3x+2|=0$ Step 2. Solve the above to get $x=-\frac{2}{3}$, thus the solution set is $\{-\frac{2}{3} \}$